Cerebral protein synthesis

Zomzely, Claire; Roberts, Sidney; Brown, Douglas M.; Provost, Carol

doi:10.1016/s0022-2836(66)80016-5

Cited by 56 publications

(10 citation statements)

References 40 publications

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“…Polysomes, as long as they carry nascent chains, do not dissociate until the Mg2+ concentration is reduced to much lower values (Fig.2) and they are not dissociated at KCl concentrations as high as 1.0 M. This greater resistance of polysomes to dissociation has been known for some time [26,27] and has been confirmed for several mammalian tissues [4,28-30,7].…”

Section: Discussionmentioning

confidence: 56%

Preparation and Properties of Ribosomal Subunits from Mouse Plasmocytoma Tumors

Mechler

Mach

1971

European Journal of Biochemistry

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Mouse myeloma ribosomes were prepared without exposure to detergent and their behavior with either decreasing concentrations of Mg2+ or increasing concentrations of KCl examined. The minimal conditions for dissociation into subunits were determined and the properties of the subunits obtained under different conditions compared. Ribosomes which are first freed of nascent chains dissociate into 40 S and 60 S subunits at physiological Mg2+ concentrations (5 mM) and at only 0.3 M KCl (K3 subunits). Although they lack one distinct protein present in low Mg2+ subunits, these K3 subunits reassociate spontaneously to form 80 S particles at lower ionic strength (0.05 M KCl) and are highly active in poly(U)‐directed polyphenylalanine synthesis. This activity is maintained after storage at—70 °C for several months. Subunits obtained at a higher concentration of KCl (0.88 M) are less active and less stable, and they lack at least one protein which is present in K3 subunits. Low Mg2+ subunits are unable to reassociate spontaneously, are inactive in the poly(U) system, have lower sedimentation coefficients, and have lost the 5 S RNA.

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Section: Discussionmentioning

confidence: 56%

Preparation and Properties of Ribosomal Subunits from Mouse Plasmocytoma Tumors

Mechler

Mach

1971

European Journal of Biochemistry

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“…The brain (approximately 500 mg) was subsequently isolated after decapitation and immediately homogenized (10% w/v homogenate) by 10 strokes in a baked, ice-cold Dounce homogenizer with 5 mL lysis buffer (no detergent, no RNase inhibitors) containing 250 mM sucrose, 50 mM Tris, pH 7.5, 100 mM KCl, and 12 mM MgCl 2 as described [58], [59]. A post-mitochondrial supernatant (S1) was obtained by spinning homogenates at 16,000 g for 10 minutes at 4°C.…”

Section: Methodsmentioning

confidence: 99%

Fmr1 Transcript Isoforms: Association with Polyribosomes; Regional and Developmental Expression in Mouse Brain

et al. 2013

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The primary transcript of the mammalian Fragile X Mental Retardation-1 gene (Fmr1), like many transcripts in the central nervous system, is alternatively spliced to yield mRNAs encoding multiple proteins, which can possess quite different biochemical properties. Despite the fact that the relative levels of the 12 Fmr1 transcript isoforms examined here vary by as much as two orders of magnitude amongst themselves in both adult and embryonic mouse brain, all are associated with polyribosomes, consistent with translation into the corresponding isoforms of the protein product, FMRP (Fragile X Mental Retardation Protein). Employing the RiboTag methodology developed in our laboratory, the relative proportions of the 7 most abundant transcript isoforms were measured specifically in neurons and found to be similar to those identified in whole brain. Measurements of isoform profiles across 11 regions of adult brain yielded similar distributions, with the exceptions of the hippocampus and the olfactory bulb. These two regions differ from most of the brain in relative amounts of transcripts encoding an alternate form of one of the KH RNA binding domains. A possible relationship between patterns of expression in the hippocampus and olfactory bulb and the presence of neuroblasts in these two regions is suggested by the isoform patterns in early embryonic brain and in cultured neural progenitor cells. These results demonstrate that the relative levels of the Fmr1 isoforms are modulated according to developmental stage, highlighting the complex ramifications of losing all the protein isoforms in individuals with Fragile X Syndrome. It should also be noted that, of the eight most prominent FMRP isoforms (1–3, 6–9 and 12) in mouse, only two have the major site of phosphorylation at Ser-499, which is thought to be involved in some of the regulatory interactions of this protein.

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“…Mammalian brain polyribosomes have been reported to be more unstable than those of other tissues (Zomzely et al, 1966(Zomzely et al, , 1968. This lability may be of some importance with regard to the polyribosome alterations that are evoked by high concentrations of phenylalanine, since the brain tissue, particularly that of neonatal animals, appears to be most susceptible (Aoki & Siegel, 1970).…”

Section: Printed In Great Britainmentioning

confidence: 99%

The mechanism of polyribosome disaggregation in brain tissue by phenylalanine

Taub¹,

Johnson²

1975

Biochemical Journal

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The injection of neonatal mice with phenylalanine resulted in a rapid decrease in brain polyribosomes and a concomitant increase in monomeric ribosomes. Animals of 1-16 days of age were equally affected by phenylalanine, although the brain polyribosomes of 60-day-old mice were relatively resistant to the effects of phenylalanine. The population of free polyribosomes appeared to be more sensitive to phenylalanine treatment than bound polyribosomes, which were somewhat more resistant to disruption by high concentrations of the amino acid. The effects of phenylalanine were more pronounced with polyribosomes in the cerebral cortex than with those in the cerebellar tissue. The mechanism of polyribosome disruption was shown to be independent of hydrolysis mediated by ribonuclease. Virtually all of the monomeric ribosomes that resulted from phenylalanine treatment were shown to be inactive with regard to endogenous protein synthesis and were present in the cell cytoplasm as vacant couples. These ribosomes were readily dissociated by treatment with 0.5 M-KCl and subsequent ultracentrifugation. These results are discussed in the light of the possibility that high concentrations of phenylalanine disrupt brain protein synthesis by a molecular mechanism that is associated with initiation events.

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Cerebral protein synthesis

Cited by 56 publications

References 40 publications

Preparation and Properties of Ribosomal Subunits from Mouse Plasmocytoma Tumors

Preparation and Properties of Ribosomal Subunits from Mouse Plasmocytoma Tumors

Fmr1 Transcript Isoforms: Association with Polyribosomes; Regional and Developmental Expression in Mouse Brain

The mechanism of polyribosome disaggregation in brain tissue by phenylalanine

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